Detailed characteristics of the free-surface shock wave (FSSW) are numerically studied for the case of waves generated about a wedge model. The MAC-type finite-difference solution method called TUMMAC-VIII is employed. The density function method is used for implementation of the nonlinear free-surface condition in the framework of a rectangular coordinate system. The computed results show that the wave front angle varies systematically and that the shock condition is fulfilled in the thin layer near the free surface, which is one of the most typical characteristics of the FSSW. Some important mechanisms of wave breaking accompanied by the FSSW, such as overturning of wave front, vortex generation and energy dissipation, are also approximately simulated.